Problem: Which of these numbers is composite? ${23,\ 29,\ 53,\ 93,\ 97}$
Answer: A composite number is a number that has more than two factors (including 1 and itself). 23, 29, 53, and 97 each have only two factors. The factors of 93 are 1, 3, 31, and 93. Thus, 93 is the composite number.